Abstract: Tagitinin D was identified as one of the main compounds present in Asteraceae,which exhibited anti-tumor activities.To explore the mechanism of apoptosis in HepG2 cells induced by tagitinin D,colony formation assay was used to detect the cell proliferation ability.Then the cell cycle and apoptosis were checked by flow cytometry,and the changes of reactive oxygen species (ROS) levels was detected by DCFH-DA,and ER stress-related protein expression levels were determined using Western blot assay.The results showed that tagitinin D increased ROS levels,inhibited the cell proliferation,arrested the cell cycle in the G2/M phase,and induced apoptosis in HepG2 cells.ER stress signaling pathway related protein levels such as PDI,Calnexin,Ero1-Lα,Bip,IRE1-Lα,and p-eIF2α are increased.In summary,all the data suggested tagitinin D induced ROS which further elicited ER stress response and led to apoptosis in HepG2 cells.

Key words: tagitinin D, ROS, apoptosis, ER stress signaling pathway